1. Field of the Invention
The present invention relates to novel naphthopyran-type compounds that have, in particular, photochromic properties. The invention also relates to photochromic compositions and photochromic ophthalmic articles (goggles, lenses and eye-shields, for example) that contain these naphthopyrans. The invention also covers the preparation of these novel naphthopyrans. The photochromic compounds are capable of changing color under the influence of a first poly- or mono-chromatic light (UV for example) and of returning to their initial color when the luminous irradiation ceases, or under the influence of temperature and/or poly- or mono-chromatic light different from the first light. The invention particularly relates to naphthopyrans having an Oxygen-containing heterocyclic group fused to the naphthopyran.
2. Background of the Art
Photochromism generally concerns the ability of a compound to reversibly change color under different light conditions. One particular type of photochromic phenomenon concerns the reversible change in color of a compound from an original color to a different color when the compound is exposed to a source of ultraviolet radiation, such as solar radiation or light radiated from a mercury or xenon lamp. The photochromic compound fades to the original color within a period of time after the photochromic compound is isolated from the ultraviolet radiation, such as by placing the compound in a dark room.
Photochromic compounds find applications in various fields, such as for the manufacture of ophthalmic lenses, contact lenses, solar protection glasses, goggles, sun screens, filters, camera optics, photographic apparatus optics or other optical devices and observation devices, glazing, decorative objects, currency elements and even for information storage by optical inscription (coding). For example, photochromic compounds, such as naphthopyrans, are incorporated into plastic ophthalmic lenses to effect color changes in the lenses when the lenses are exposed to particular lighting conditions. Additionally, different photochromic compounds may be blended together to create a color effect that is different from respective color effects of the individual photochromic compounds. As an example, a first photochromic compound that turns orange or red when activated by light and a second photochromic compound that turns blue when activated by light may be blended together to form a photochromic mixture that produces a shade of gray when activated by light.
In the field of ophthalic optics, and in particular the field of spectacles, a photochromic lens that comprises one or more photochromic compounds is usually required to have:
a high transmission level in the visible region in the absence of ultraviolet radiation,
a low transmission (high colorability) under solar irradiation (especially with ultraviolet exposure),
desired coloration and discoloration kinetics, e.g., high sensitivity to irradiation and fast bleaching,
a high solubility in hosting materials,
a tint acceptable to the consumer (gray or brown preferably) with the chosen tint maintained during the coloration and the discoloration of the lens,
a maintenance of the performance and properties, within a temperature range of 0-40xc2x0 C.,
a significant durability, since these objectives sought after are used in sophisticated corrective lenses and are therefore expensive.
These lens characteristics are primarily determined by the active photochromic compounds. These compounds must furthermore be compatible with the organic or inorganic support that constitutes the lens.
Moreover, it is to be noted that obtaining a neutral gray or brown tint may necessitate the use of at least two photochromes of different colors, i.e., two separate compounds having distinct maximal absorption wavelengths in the visible region of the electromagnetic spectrum. The use of combinations of photochromic compounds imposes other requirements on both the individual photochromic compounds and the groups of photochromic compounds. In particular, the coloration and discoloration kinetics of the (two or more) combined active photochromic compounds must be essentially identical. The same applies for their stability with time, and also for their compatibility with a single plastic or inorganic support.
Amongst the numerous photochromic compounds described in the prior art, benzopyrans or naphthopyrans are described in patents or patent applications U.S. Pat. Nos. 3,567,605; 3,627,690; 4,826,977; 5,200,116; 5,238,981; 5,411,679; 5,429,744; 5,451,344; 5,458,814; 5,651,923; 5,645,767; 5,698,141; WO-A-95 05382; WO-A-96-14596; WO-A-97 21698 which are of the reduced formula below: 
U.S. Pat. Nos. 5,651,923 and 6,018,059 more specifically describe naphthopyrans having benzofurano or naphthofurano groups fused to the naphthalene ring of naphthopyran (the general structures are shown below). 
The various substitutent groups are defined in the various patents and encompass a wide, art-accepted range of combinations of substitutents intended to provide specific physical or photochromic properties. These compounds claim to satisfy the specifications identified above as needed for photochromic compounds. In reality, even if these compounds really do have one or more of the basic properties sought after, such as a high transmission in the absence of ultraviolets and a high colorability under solar irradiation, none of the compounds described hitherto have the complete combination of properties necessary for the production of satisfactory articles. In particular, none of these compounds is intrinsically gray or brown, and the necessity of using an additional photochromes in order to obtain one of these two tints does subsist.
A novel family of molecules is described having particularly advantageous photochromic properties, such as, two intense absorption bands in the visible range and absorption bands that cover a significant part of visible spectrum (400-700 nm). This novel type of compound adapts or blends well in association with red and/or yellow complementary photochromes to give brown or gray tints.
According to a first aspect of the invention is described Naphthopyran having a central nucleus of the formula: 
wherein F is an oxygen-containing 5- to 7-member heterocyclic ring group, its 2,3 or 3,2 positions fused to the f, i, j, or k side of the ring, and
R1 and R2 are the atoms or groups providing photochromic properties to the naphthopyran.
This naphthopyran may preferably have R1 is selected from the group consisting of a hydrogen, a linear or branched alkyl group of 1 to 12 carbon atoms, a cycloalkyl group of 3 to 12 carbon atoms, an aryl group of 6 to 24 ring carbon atoms or a heteroaryl group of 4 to 24 carbon atoms and at least one hetero ring atom selected from sulfur, oxygen and nitrogen; and wherein R1 and R2 together form an adamantyl, norbornyl, fluorenylidene, di(C1-C6)alkylanthracenylidene or spiro(C5-C6)cycloalkylanthracenylidene group.
Another aspect is a naphthopyran having the central nucleus of the formula: 
wherein F is an oxygen-containing 5- to 7-member heterocyclic ring group, its 2,3 or 3,2 positions fused to the f, i, j, or k side of the ring, and
R1 and R2 are the atoms or groups necessary to provide photochromic properties to the naphthopyran and R5 and R6 are selected from the group consisting of:
a hydrogen,
a halogen,
a linear or branched alkyl group of 1 to 12 carbon atoms,
a cycloalkyl group of 3 to 12 carbon atoms,
a linear or branched alkoxy group of 1 to 12 carbon atoms,
a linear or branched alkenyl or alkynyl group of 1-12 carbon atoms,
a linear or branched alkenyloxy or alkynyloxy group of 1-12 carbon atoms,
an aryl or heteroaryl group, and
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, of 1 to 4 carbon atoms.
According to another aspect of the present invention, naphthopyran compounds of the following formula (I) are described and enabled: 
in which:
F is an at least one oxygen-containing, 5- to 7-member heterocyclic ring group with or without substitutions. Its 2,3 or 3,2 positions are fused to the f, i, j, or k side of the naphthopyran as identified in Formula (I);
R1 and R2, for example, may independently represent:
a hydrogen,
a linear or branched alkyl group which comprises 1 to 12 carbon atoms (with or without substitution),
a cycloalkyl group which comprises 3 to 12 carbon atoms,
an aryl or heteroaryl group which comprises in its basic structure (that is, in its ring atoms, the rings comprising 5, 6 or 7 atoms) 6 to 24 carbon atoms or 4 to 24 carbon atoms respectively and at least one heteroatom selected from sulfur, oxygen and nitrogen; the basic structure being optionally substituted with at least one substituent selected from:
a halogen atom (e.g., fluorine, chlorine and bromine),
a hydroxy group,
a linear or branched alkyl group comprising 1 to 12 carbon atoms,
a linear or branched alkoxy group comprising 1 to 12 carbon atoms,
a haloalkyl or haloalkoxy group corresponding to the (C1-C12) alkyl or alkoxy groups above respectively which are substituted with at least one halogen atom, and notably a fluoroalkyl group of this type,
a linear or branched alkenyl group comprising 2 to 12 carbon atoms, and notably a vinyl group or an allyl group,
an xe2x80x94NH2 group,
an xe2x80x94NHR11 group, R11 representing a linear or branched alkyl group comprising 1 to 6 carbon atoms,
a 
xe2x80x83group, in which R12 and R13, which are the same or different, independently representing a linear or branched alkyl group comprising 1 to 6 carbon atoms, or representing (together with the nitrogen atom to which they are bound) a 5- to 7-membered ring which can comprise at least one other heteroatom selected from oxygen, sulfur and nitrogen, said nitrogen being optionally substituted with an R14 group, which is a linear or branched alkyl group comprising 1 to 6 carbon atoms,
a methacryloyl group or an acryloyl group,
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, comprising 1 to 4 carbon atoms and the aryl and heteroaryl groups having the definitions given above, or
the two substituents R1 and R2 together forming ring group such as those represented by an adamantyl, norbornyl fluorenylidene, 5,5- or 10,10-di(C1-C6)alkylanthracenylidene, 5 (or 10)-(C1-C6)alkyl-5 (or 10)-OH (or OR15)anthracenylidene or spiro(C5-C6)cycloalkylanthracenylidene ring group; said ring group being optionally substituted with at least one of the substituents listed above in the definitions for R1, R2; said ring group being optionally substituted with two adjacent groups that form a 5- to 6-member aromatic or non-aromatic ring which can comprise at least one heteroatom selected from oxygen, sulfur, and nitrogen.
R5 and R6 are identical or different and they represent, independently:
a hydrogen,
a halogen, and notably fluorine, chlorine or bromine,
a linear or branched alkyl group which comprises 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a cycloalkyl group comprising 3 to 12 carbon atoms,
a linear or branched alkoxy group comprising 1 to 12 carbon atoms (most advantageously 1 to 6 carbon atoms),
a haloalkyl, halocycloalkyl, or haloalkoxy group corresponding to the alkyl, cycloalkyl, alkoxy groups above respectively, which are substituted with at least one halogen atom, notably selected from fluorine, chlorine and bromine,
a linear or branched alkenyl or alkynyl group comprising 1-12 carbon atoms, preferably a vinyl or allyl group,
a linear or branched alkenyloxy or alkynyloxy group comprising 1-12 carbon atoms, preferably an allyloxy group,
an aryl or heteroaryl group having the same definition as that given above for aryl or heteroaryl groups within the definitions of R1, R2,
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, comprising 1 to 4 carbon atoms, and the aryl and heteroaryl groups having the same definitions as those given above for R1, R2,
an amine or amide group: xe2x80x94NH2, xe2x80x94NHR11, xe2x80x94CONH2, xe2x80x94CONHR11, 
R11, R12, and R13 having their respective definitions given above for the amine substituents of the values R1, R2,
a xe2x80x94C(R16)2X group, wherein X is xe2x80x94CN, halogen, hydroxy, alkoxy, benzoyloxy, C1-C6 acyloxy, amino, C1-C6 mono-alklamino, C1-C6 dialkyl amino, morpholino, piperidino, 1-indolinyl, pyrrolidyl, or trimethylsilyloxy, R16 is hydrogen, C1-C6 alkyl, phenyl or naphthyl with C1-C6 alkyl or C1-C6 alkoxy substituents,
an xe2x80x94OCOR17 or xe2x80x94COOR17 group, R17 representing a straight or branched alkyl group comprising 1 to 6 carbon atoms, or a cycloalkyl group comprising 3 to 6 carbon atoms, or a phenyl group, optionally substituted with at least one of the substituents listed above within the values in the definitions of R1, R2,
a methacryloyl group or an acryloyl group, an epoxy group having the formula, 
in which k=1, 2 or 3,
R5 and R6 together form a 5- to 7-member aromatic or non-aromatic ring which can comprise at least one heteroatom selected from oxygen, sulfur, and nitrogen, and/or at least one substituent selected from the group consisting of a C1 to C6 alkyl gou which is linear or bracnched, a C1 to C6 alkoxy group which is linear or branched, and an amine group of formula xe2x80x94NH2, NHR11, or 
as defined in R1 and R2 for amine groups,
a polyether, polyamide, polycarbonate, polycarbamate, polyurea or polyester residue;
each R7 group can be same or different, independently representing
a hydrogen, a halogen, and notably fluorine, chlorine or bromine,
a linear or branched alkyl group which comprises 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a cycloalkyl group comprising 3 to 12 carbon atoms,
a linear or branched alkoxy group comprising 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a haloalkyl, halocycloalkyl, or haloalkoxy group corresponding to the alkyl, cycloalkyl, alkoxy groups described above respectively, which are substituted with at least one halogen atom, notably selected from fluorine, chlorine and bromine,
a linear or branched alkenyl or alkynyl group comprising 1-12 carbon atoms, preferably a vinyl or allyl group,
a linear or branched alkenyloxy or alkynyloxy group comprising 1-12 carbon atoms, preferably a allyloxy group,
an aryl or heteroaryl group having the same definition as that given supra for R1, R2,
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, comprising 1 to 4 carbon atoms, and the aryl and heteroaryl groups having the same definitions as those given above for R1, R2,
an amine or amide group, such as xe2x80x94NH2, xe2x80x94NHR11, xe2x80x94CONH2, xe2x80x94CONHR11, 
R9, R10, and R12 having their respective definitions given above for the amine substituents and for the definitions of R1, R2,
a xe2x80x94C(R16)2X group, wherein X is xe2x80x94CN, halogen, hydroxy, alkoxy, benzoyloxy, C1-C6 acyloxy, amino, C1-C6 mono-alklamino, C1-C6 dialkyl amino, morpholino, piperidino, 1-indolinyl, pyrrolidyl, or trimethylsilyloxy, R16 is hydrogen, C1-C6 alkyl, phenyl or naphthyl with C1-C6 alkyl or C1-C6 alkoxy substituents,
an xe2x80x94OCOR17 or xe2x80x94COOR17 group, R17 representing a straight or branched alkyl group comprising 1 to 6 carbon atoms, or a cycloalkyl group comprising 3 to 6 carbon atoms, or a phenyl group, optionally substituted with at least one of the substituents listed above for the values of R1, R2: aryl or heteroaryl,
a methacryloyl group or an acryloyl group, an epoxy group having the formula, 
in which k=1, 2 or 3,
a polyether, polyamide, polycarbonate, polycarbamate, polyurea or polyester residue,
m is an integer from 0 to 2;
each R8 group can be the same or different, independently representing
a hydrogen,
a halogen, and notably fluorine, chlorine or bromine,
a linear or branched alkyl group which comprises 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a cycloalkyl group comprising 3 to 12 carbon atoms,
two of the R8 groups, which are adjacent or bonded to the same carbon atom in the group F, form a 5- to 7-membered non-aromatic ring which can comprise at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen,
n is an integer from 0 to 4.
The terms xe2x80x9cgroupxe2x80x9d and xe2x80x9ccentral nucleusxe2x80x9d have established meanings according to the practice of the present invention. Where the term xe2x80x9cgroupxe2x80x9d is used, the chemical unit described is intended to include and allow for substituents consistent with the primary chemical unit. For example, where the term alkyl group is used, that term is intended to include classic alkyl materials such as methyl, ethyl, propyl, butyl, hexyl, octyl, iso-octyl, dodecyl, cyclohexyl and the like, and is also intended to include alkyl units with substitution thereon consistent with the underlying nature of an alkyl unit, such as hydroxymethyl, bromoethyl, dichloropropyl, 1,2,3,4-tetrachlorobutyl, omega-cyanohexyl and the like. Where the term xe2x80x9calkyl moietyxe2x80x9d is used, no substitution is allowed.
The terminology of a central nucleus of a provided formula has a similar meaning. The term indicates that the formula, even though atoms are shown in the formula, may be substituted with any chemical units as long as the underlying bond structure of the formula is not altered. For example, where the term a central nucleus of the formula 
is used, there may be any substitution at such positions as 3, 4, 5, 6, 7, 8, 9, or 10 as long as the structure of F is not destroyed and the bond structure shown (e.g., the double bonds) are not converted to single bonds (e.g., by attempting to provide two substituents at the 6-position, which would require elimination of the double bond between positions 5 and 6. Where the term a compound of the formula is used, except for description of the term xe2x80x98groupxe2x80x99 in definitions, no unspecified substitution is allowed.
Where the term xe2x80x98groupxe2x80x99 or xe2x80x98central nucleusxe2x80x99 is used in the practice of the present invention, those terms refer to the capability of the structure to have substitution or not on the chemical unit or not. The term xe2x80x98groupxe2x80x99 refers to any chemical structure, while the term xe2x80x98central nucleusxe2x80x99 refers specifically to a ring structure as the core chemical moiety. For example, an xe2x80x98alkyl groupxe2x80x99 includes unsubstituted n-alkyl, iso-alkyl, methyl ethyl, octyly, iso-octyl, docecyl, and the like, and substituted alkyl such as hydroxymethyl, 1-chloroethyl, 2-cyano-butyl, 3-ethyl-4-hexyl, omega-carboxy-pentyl, and the like. Where the term xe2x80x98moietyxe2x80x99 is used, as in the term alkyl moiety is used, that term refers to only unsubstituted chemical units. Similarly, where the term xe2x80x98central nucleusxe2x80x99 is used, such as in the central nucleus of a naphthyl, any substituent may be present on the central nucleus of the naphthyl group, such as 1-methyl-, 2-chloro-, 2,4-dimethoxy-, 2,2xe2x80x2-dimethoxy-, and the like. Where the term having a structure of the specific formula is used, no substitution is allowed beyond that of the described formula.
Among the substituents that can be considered for the compounds of formula (I) according to the invention, groups should be considered that comprise and/or form at least one function which can be polymerized and/or crosslinked, which group are preferably selected from the following list: alkenyl, advantageously vinyl, methacryloyl, acryloyl, acryloxyalkyl, methacryloxyalkyl or epoxy.
Thus, the photochromic compounds according to the invention can be monomers, of different types or not, that can react with each other or with other comonomers to form homopolymers and/or copolymers that bear a photochromic functionality and possess mechanical properties of macromolecules. It follows that one of the objects of the present invention consists of these homopolymers or copolymers comprising (co)monomers and/or of crosslinked compounds, that, at least in part, consist of photochromic compounds (I) according to the invention.
In the same general concept, the above-mentioned compounds (I) can be crosslinking agents that have one or more reactive functions capable of allowing the formation of bridges between chains of polymers of photochromic nature or not. The crosslinked compounds that can be obtained in this manner also are a part of the present invention.
Amongst such compounds according to formula (I), preferred photochromic are those which have the formula (Ia), (Ib), (Ic), and (Id) below: 
in which:
X is a carbon or oxygen atom,
m is an integer 1 or 2,
R1 and/or R2, independently represent optionally substituted aryl or heteroaryl groups the basic structure of which is selected from those of phenyl, naphthyl, biphenyl, pyridyl, furyl, benzofuryl, dibenzofuryl, Nxe2x80x94(C1-C6)alkylcarbazole, thienyl, benzothienyl, dibenzothienyl, julolidinyl groups; R1 and/or R2 advantageously representing a para-substituted phenyl group or R1 and R2 together form an adamantyl group or norbornyl group or anthracenylidene group;
R5 and R6 are the same or different, and may represent independently
a hydrogen,
a linear or branched alkyl group that comprises 1 to 6 carbon atoms,
a xe2x80x94C(R16)2X group, wherein X is hydroxy, alkoxy, benzoyloxy, C1-C6 acyloxy, an amine or amide group: xe2x80x94NH2, xe2x80x94NHR11, xe2x80x94N(R11)2, xe2x80x94CONH2, xe2x80x94CONHR11, xe2x80x94CON(R11)2, R16 is hydrogen, C1-C6 alkyl, phenyl or naphthyl with C1-C6 alkyl or C1-C6 alkoxy substituents,
an optionally substituted phenyl or benzyl group,
a xe2x80x94COR17, or xe2x80x94COOR17 group, R17 representing a linear or branched alkyl group comprising 1 to 6 carbon atoms,
or R5 and R6 together form a 5- to 7-member aromatic or non-aromatic ring which can comprise at least one heteroatom selected from oxygen, sulfur, and nitrogen, and/or at least one substituent selected from the group consisting of a C1 to C6 alkyl gou which is linear or bracnched, a C1 to C6 alkoxy group which is linear or branched, and an amine group of formula xe2x80x94NH2, NHR11, or 
as defined in R1 and R2 for amine groups;
R7 and R9 are the same or different, and may represent independently
a hydrogen,
a halogen, and notably fluorine, chlorine or bromine,
a linear or branched alkyl group which comprises 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a cycloalkyl group comprising 3 to 12 carbon atoms,
a linear or branched alkoxy group comprising 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a haloalkyl, halocycloalkyl, or haloalkoxy group corresponding to the alkyl, cycloalkyl, alkoxy groups above respectively, which are substituted with at least one halogen atom, notably selected from fluorine, chlorine and bromine,
a linear or branched alkenyl or alkynyl group comprising 1-12 carbon atoms, preferably a vinyl or allyl group,
a linear or branched alkenyloxy or alkynyloxy group comprising 1-12 carbon atoms, preferably a allyloxy group,
an aryl or heteroaryl group having the same definition as that given supra for R1, R2,
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, comprising 1 to 4 carbon atoms, and the aryl and heteroaryl groups having the same definitions as those given supra for R1, R2,
an amine or amide group: xe2x80x94NH2, xe2x80x94NHR11, xe2x80x94NR12R13, R11, R12, R13 having their respective definitions given supra for the amine substituents of the values R1, R2, R12 and R13 can form a saturated or unsaturated ring with or without substituents;
R8, which are identical or different, represent, independently
a hydrogen,
a linear or branched alkyl group which comprises 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a cycloalkyl group comprising 3 to 12 carbon atoms,
a xe2x80x94C(R16)2X group, wherein X is hydroxy, C1-C6 alkoxy, benzoyloxy, C1-C6 acyloxy, an amine or amide group: xe2x80x94NH2, xe2x80x94NHR11, xe2x80x94NR12R13, R11, R12, R13 having their respective definitions given supra for the amine substituents of the values R1, R2, R12 and R13 can form a saturated or unsaturated ring with or without substituents, R16 is hydrogen, C1-C6 alkyl, phenyl or naphthyl with C1-C6 alkyl or C1-C6 alkoxy substituents,
These compounds present particularly advantageous photochromic properties, such as, having strong coloration ability with two absorption bands in the visible range with high xcexmax values. These compounds are also preferably stable and compatible with matrices made of at least one organic polymer or mineral material (e.g., inert inorganic binder), both in the form included in the matrix and in the form of a coating.
In a solution or in the polymer matrix, the compounds according to the invention are colorless or slightly colored in the initial state and they rapidly develop an intense coloration under UV light (365 nm) or a luminous source of the solar type. They rapidly recover their initial color when the irradiation stops.
The compounds of the invention can be obtained by the condensation of a derivative of 1-naphthol that is suitably substituted and a derivative of propargyl alcohol. The condensation can be carried out in organic solvents, particularly non-polar solvents such as toluene, xylene or tetrahydrofuran and, optionally, in the presence of a catalyst, acid catalysts, and especially acid catalysts such as fluorinated organic acid catalysts, p-toluenesulfonic acid, chloroacetic acid or acid aluminic acid): 
These synthetic routes are classical and have been described in the above-mentioned references of the prior art as well as in U.S. Pat. No. 4,818,096. The propargyl alcohols are either commercially available or easily synthesized by the reaction of lithium acetylide or ethynyl (magnesium bromide) with the corresponding ketones (R1)CO(R2). The ketones are also either commercially available or easily synthesized by the classical methods, for example, the Friedel-Crafts reaction from an acid chloride.
The derivatives of 1-naphthol are obtained by various methods adapted from the literature. Below we give some references on methods that allow the synthesis of the compounds of the invention.
Method 1: Johnson et al. Org. React. 1951, Vol. 6, p. 1. 
Method 2: U.S. Pat. No. 5,200,116 (Example 2) or U.S. Pat. No. 6,207,084
Method 3: Cameron et al., Aust. J. Chem., 1983, 35, p1481
DIBAL-H: diisobutoxyaluminum hydride, pTsOH: p-toluenesulphonic acid, MeOH: methanol, CITBS: chloro-dimethyl-t-butyl silane, PCC: pyridium chlorochrome, W-K: Wolff-Kishiner reduction.
The starting aldehyde in Method 1 can be prepared according to the route described in B. J. Bradbury, etal., J. Heterocyclic Chem., 26, 1827 (1989), and the starting ketone in Method 2 can be prepared according to the procedure in U.S. Pat. No. 6,210,608. Aromatic aldehydes can also be prepared through the Vilsimeier formylation (cf. Vilsmeier, A.; Haack, A. Ber., 1927, 60, 119)
Regarding the commercial application of compounds according to the present invention, it should be noted that they can be used as a photochromic material dispersed in the composition of a polymer matrix. They can also be used in solution.
A photochromic solution can be obtained by dissolving the compound in an organic solvent, such as toluene, dichloromethane, tetrahydrofuran or ethanol. The solutions obtained are generally colorless and transparent. When exposed to sunlight, they develop a strong coloration and they recover the color of this state when placed in an environment with lesser exposure to solar radiation or, in other words, when they are no longer exposed to UV radiation. In general, a very low concentration of products (on the order of 0.01-5% by weight or volume) is sufficient to obtain an intense coloration.
The most interesting applications are those in which the photochrome is dispersed uniformly within or on the surface of a polymer, copolymer or mixture of polymers. The implementation methods that can be considered are of a great variety. Among those known to a person skilled in the art, one can cite, for example, diffusion in the (co)polymer, from a suspension or solution of the photochrome, in a silicone oil, in an aliphatic or aromatic hydrocarbon, in a glycol, or from another polymer matrix. Currently the diffusion is carried out at a temperature of 50-200xc2x0 C. for a duration of 15 minutes to several hours, depending on the nature of the polymer matrix. Another implementation technique consists in mixing the photochrome in a formulation of polymerizable materials, in depositing this mixture on a surface or in a mold and in then carrying out the polymerization. These implementation techniques and others are described in the article by CRANO et al. xe2x80x9cSpiroxazines and their use in photochromic lenses,xe2x80x9d published in Applied Photochromic Polymer Systems, Publishers Blackie and Son Ltd., 1992. According to a variant of the invention, it is also possible to consider grafting the photochromes onto (co)polymers. Thus, another aspect of the invention consists of the (co)polymers grafted with at least one of the photochromes described above.
As examples of preferred polymer materials for optical applications of the photochromic compound according to the invention, one can mention the following products: alkyl, cycloalkyl, aryl or arylalkyl poly(mono-, di-, tri-, tetra)acrylate or poly(mono-, di-, tri-, tetra) methacrylate, optionally halogenated or comprising at least ether and/or ester and/or carbonate and/or carbamate and/or thiocarbamate and/or urea and/or amide group; polystyrene, polycarbonate (e.g., bisphenol A polycarbonate, poly(carbonate of diallyl diethylene glycol), polyepoxy, polyurethane, polythiourethane, polysiloxane, polyacrylonitrile, polyamide, aliphatic or aromatic polyester, vinyl polymers, cellulose acetate, cellulose triacetate, cellulose acetate-propionate or polyvinylbutyral, copolymers of two or more types of monomers or mixtures of the above-mentioned polymers, preferably polycarbonate-polyurethane, poly(meth)acrylate-polyurethane, polystyrene-poly(meth)acrylate or polystyrene-polyacrylonitrile, advantageously a mixture of polyester and/or polycarbonate or poly(meth)acrylate.
The quantity of photochrome used in various articles depends on the desired degree of darkening. In particular, it is used in a quantity of 0.001-20 wt % of the total weight of the layer in which the photochrome is included. The photochromic compounds according to the invention can be used alone or in a mixture with other products to form a composition that can be in solid or liquid form, for example, in a solution or in a dispersion, as has already been mentioned above. These compositions, which constitute another object of the invention, can comprise one or more compounds (I) according to the invention and other complementary photochromic compounds which allow the attaining of dark colorations, for example, gray or brown, which the public desires in applications such as ophthalmic or sun-protection eyewear. These additional photochromic compounds can be those known to a person skilled in the art and described in the literature, for example, other naphthopyrans, benzopyrans, chromenes (U.S. Pat. Nos. 3,567,605, 5,238,981, World Patent No. 9,422,850, European Patent No. 562,915), spiropyrans or naphthospiropyrans (U.S. Pat. No. 5,238,981) and spiroxazines (CRANO et al., xe2x80x9cApplied Photochromic Polymer Systems,xe2x80x9d Publishers Blackie and Son Ltd., 1992, Chapter 2).
These compositions according to the invention can also comprise:
Non-photochromic dyes allowing the adjustment of the tint,
and/or one or more stabilizers, such as, for example, an antioxidant,
and/or one or more anti-UV screens,
and/or one or more anti[free]radical agents,
and/or deactivators that deactivate the states of photochemical excitation.
These additives can enable further improvements in the durability of said compositions.
According to another one of its aspects pertaining to the application of the photochromic compounds (I), the present invention also relates to ophthalmic articles, such as articles of ophthalmic or sun protection eyewear articles, or eye shields comprising at least one compound according to the invention and/or at least one (co)polymer formed, at least in part, of repeating units derived from compounds having formula (I) and/or at least one composition comprising compounds (I) according to the invention, as defined above, and/or at least one matrix, as defined above, made of an organic polymer material or a mineral material or a mineral-organic hybrid material incorporating at least one compound of the invention.
In practice, the articles to which the present invention applies more particularly are photochromic ophthalmic or sun-protection lenses, glass paneling (glasses for buildings, for locomotion devices, automobiles), optical devices, decorative articles, sun-protection articles, information storage, etc.